1 definition by Lolitaslut
To burst into loud, hysterical or aggressive verbal abuse. Used primarily in Ireland and the UK. Similar with the American "freak the fuck out," however only used in negative situations.
"Yer wan at the pub cracked up at me when I asked how much she charged for an hour."
"Don't you dare crack up at me! I'm not the one sleepin' with my sister!"
"Don't you dare crack up at me! I'm not the one sleepin' with my sister!"
by Lolitaslut May 7, 2009